This invention relates to electrical connecting means for forming electrical connections to extremely fine wires, for example, wires in the range of AWG 32-50. Wires in this gauge range are frequently used for coil windings in many types of electrical devices and they are ordinarily insulated with a varnish type insulation such as polyvinyl formal resin. The electrical coils are usually quite small in themselves and it is desirable to have a terminal or other connecting means which is as small as possible for the coils.
U.S. Pat. No. 4,026,013 discloses and claims a connecting means for extremely fine wires in the form of an insulating body having a cavity therein which receives a trapezoidal shaped terminal device. One external surface of the terminal device is provided with serrations which penetrate the varnish type insulation of the wire when the wire is forced against this surface. The terminal device is slightly oversized relative to the dimensions of the cavity so that it is collapsed to some extent when it is forced into the cavity. In accordance with the teachings of U.S. Pat. No. 4,026,013, a portion of the wire is located against one wall of the cavity and the terminal is thereafter forced into the cavity with the serrated surface against the wire. The partial collapse of the terminal results in the accumulation of stored energy in the terminal which urges the serrated surface of the terminal against the wire so that electrical contact is established with the wire and the stored energy of the terminal assures the achievement of a stable and long lived electrical connection.
Connecting means of the type shown in the above identified U.S. Pat. No. 4,026,013 have received an enthusiastic reception in the electrical industry, particularly among manufacturers faced with the problem of forming electrical connections to the wires of relatively small coils. While the electrical connecting means shown in that patent is quite small, there are nonetheless circumstances where an even smaller terminal and connecting means are required. The instant invention is, therefore, directed to the achievement of an electrical connecting means of the general class disclosed in U.S. Pat. No. 4,026,013 which is, however, significantly smaller, other things being equal, than the connecting means of the prior art and which can, therefore, be used under extremely demanding circumstances as regards space limitations.
In accordance with the teachings of the instant invention, a terminal is provided which has a contact arm and a wedge arm which is disposed beside, and held slidably against, the contact arm. The terminal is dimensioned to be received in a cavity provided in a coil bobbin or the like in which a portion of the wire is positioned. The terminal is then inserted into the cavity with the contact arm extending beside the wire and the wedge arm is thereafter slid along the contact arm and serves to force the contact arm against the wire and clamp the wire against a side of the cavity. Serrations are provided in the contact arm as taught in U.S. Pat. No. 4,026,013 for penetrating the varnish type insulation of the wire and establishing the electrical contact. Furthermore, the contact arm and the wedge arm are constructed such that after the wedge arm is moved to its wedging position, stored energy is accumulated in the terminal which maintains the contact arm in intimate engagement with the wire.
It is accordingly an object of the invention to provide an electrical connecting means for extremely fine wires. A further object is to provide a connecting means of extremely small size which can be used under restricted spatial circumstances. A further object is to provide a connecting means comprising a cavity and a terminal which is insertable into the cavity to form an electrical connection with a wire disposed in the cavity. A further object is to provide a terminal for establishing contact with extremely fine wires which can be manufactured at a minimum of cost by conventional die stamping and forming methods.